Fix Yosys

[belanoa]

Some small modifications to the code to make it compatible with Yosys

[yvantor]

This is good for temporarily fixing open-source-tools-based design flows, but I think the organization should be changed quite much. For example, most of the defines files that changed name contain defines that became parameters, and in general defines can be exported with Bender without needing to create specific files. I think this was used for integration in a "complete" PULP system (pulp_soc + pulp_cluster), but I think a PULP system could also be updated with a cleaner structure. Long story short, @belanoa before closing this, could you open an issue stating these problems? I would suggest opening it here and in the PULP repo.